Question: Before the previous stop there were 28 people riding on a train. 1 person ended up getting off at the stop. How many people are riding the train now?
Solution: The number riding the train now is the difference between the number who were riding and the number who got off at the previous stop. The difference is $28 - 1$ people on the train. $28 - 1 = 27$ people are on the train.